Blowing on hot food helps to cool it down by facilitating heat transfer through a process called convection. While heat is indeed tied to molecular movement, blowing air over hot food enhances the rate of heat transfer from the food to the surrounding environment, which makes the food feel cooler.
When you blow on hot food, you are essentially increasing the flow of air around it. As the air moves across the surface of the food, it carries away the heat from the food by convection. Convection is the transfer of heat through the movement of a fluid (in this case, air) due to the differences in temperature.
As the air molecules in the blown air make contact with the hot surface of the food, they absorb some of the heat energy from the food. The air molecules, now carrying the heat, move away from the food, and cooler air molecules replace them. This continuous movement of air molecules ensures that there is a constant supply of cooler air in contact with the hot food.
Additionally, blowing on hot food also increases the evaporation of any moisture present on the food's surface. As the moisture evaporates, it takes away a significant amount of heat energy from the food, further contributing to the cooling effect.
Overall, blowing on hot food increases the rate of heat transfer from the food to the surrounding air, helping to cool it down more quickly than if it were left to cool on its own.